perf: cache-only strategy for list views, cache-then-cw for single fetch

- Add data-source hierarchy to opportunity manager (cache-only, cache-then-cw, cw-first)
- fetchPages/search/fetchByCompany use cache-only: Redis → DB (no CW calls)
- fetchItem uses cache-then-cw by default, cw-first when fresh=true
- Add idleTimeout: 255 to Bun.serve to prevent request timeouts
- Map CW status 57 (04. Confirmed Quote) to Active equivalency
- Add computeCacheTTL algorithm and opportunityCache module

src/modules/algorithms/computeCacheTTL.ts

@@ -0,0 +1,166 @@
+/**
+ * @module computeCacheTTL
+ *
+ * Adaptive Cache TTL Algorithm
+ * ============================
+ *
+ * Determines how long a cached record should live before it must be
+ * re-fetched from the upstream source (e.g. ConnectWise API).
+ *
+ * The algorithm prioritises freshness for records that are actively
+ * being worked on, while avoiding unnecessary API calls for stale or
+ * inactive data.
+ *
+ * ## Spec
+ *
+ * | # | Condition                                                        | TTL (ms) | TTL (human) | Rationale                                                          |
+ * |---|------------------------------------------------------------------|----------|-------------|--------------------------------------------------------------------|
+ * | 1 | `closedFlag` is `true`                                           | `null`   | Do not cache| Closed records are rarely accessed; caching wastes memory.         |
+ * | 2 | `expectedCloseDate` OR `lastUpdated` is within the last **5 days**| 30 000   | 30 seconds  | High-activity window — data changes frequently and must stay fresh.|
+ * | 3 | `expectedCloseDate` OR `lastUpdated` is within the last **14 days**| 60 000  | 60 seconds  | Moderate activity — still relevant, but changes less often.        |
+ * | 4 | Everything else (older than 14 days)                             | 900 000  | 15 minutes  | Low activity — safe to serve from cache for longer.                |
+ *
+ * ## Evaluation order
+ *
+ * Rules are evaluated **top-to-bottom**; the first matching rule wins.
+ * Rule 2 (5-day window) is a subset of Rule 3 (14-day window), so it
+ * must be checked first.
+ *
+ * ## Inputs
+ *
+ * | Field              | Type             | Description                                                        |
+ * |--------------------|------------------|--------------------------------------------------------------------|
+ * | `closedFlag`       | `boolean`        | Whether the record is closed / inactive.                           |
+ * | `expectedCloseDate`| `Date \| null`   | The projected close date (future-looking relevance signal).        |
+ * | `lastUpdated`      | `Date \| null`   | The last time the upstream record was modified (backward-looking). |
+ * | `now`              | `Date` (optional)| Override for the current timestamp; defaults to `new Date()`.      |
+ *
+ * ## Output
+ *
+ * Returns `number | null`:
+ * - A positive integer representing the TTL in **milliseconds**, or
+ * - `null` when the record should **not** be cached at all.
+ *
+ * ## Usage
+ *
+ * ```ts
+ * import { computeCacheTTL } from "../modules/algorithms/computeCacheTTL";
+ *
+ * const ttl = computeCacheTTL({
+ *   closedFlag: opportunity.closedFlag,
+ *   expectedCloseDate: opportunity.expectedCloseDate,
+ *   lastUpdated: opportunity.cwLastUpdated,
+ * });
+ *
+ * if (ttl !== null) {
+ *   await redis.set(key, serialised, "PX", ttl);
+ * }
+ * ```
+ */
+
+// ---------------------------------------------------------------------------
+// Constants
+// ---------------------------------------------------------------------------
+
+/** 30 seconds – TTL for high-activity records (within 5 days). */
+export const TTL_HIGH_ACTIVITY = 30_000;
+
+/** 60 seconds – TTL for moderate-activity records (within 14 days). */
+export const TTL_MODERATE_ACTIVITY = 60_000;
+
+/** 15 minutes – TTL for low-activity / stale records. */
+export const TTL_LOW_ACTIVITY = 900_000;
+
+/** 30 days in milliseconds. */
+const THIRTY_DAYS_MS = 30 * 24 * 60 * 60 * 1000;
+
+/** 5 days in milliseconds. */
+const FIVE_DAYS_MS = 5 * 24 * 60 * 60 * 1000;
+
+/** 14 days in milliseconds. */
+const FOURTEEN_DAYS_MS = 14 * 24 * 60 * 60 * 1000;
+
+// ---------------------------------------------------------------------------
+// Input type
+// ---------------------------------------------------------------------------
+
+export interface CacheTTLInput {
+  /** Whether the record is closed / inactive. */
+  closedFlag: boolean;
+  /** When the record was closed — used for recently-closed caching (within 30 days). */
+  closedDate: Date | null;
+  /** The projected close date — serves as a forward-looking relevance signal. */
+  expectedCloseDate: Date | null;
+  /** The date the upstream record was last modified — backward-looking signal. */
+  lastUpdated: Date | null;
+  /**
+   * Override for the current timestamp.
+   * Useful for deterministic testing. Defaults to `new Date()`.
+   */
+  now?: Date;
+}
+
+// ---------------------------------------------------------------------------
+// Algorithm
+// ---------------------------------------------------------------------------
+
+/**
+ * Compute the cache TTL for a record based on its activity signals.
+ *
+ * @param input - The record's activity signals. See {@link CacheTTLInput}.
+ * @returns The TTL in milliseconds, or `null` if the record should not be cached.
+ *
+ * @see Module-level JSDoc for the full spec table and evaluation rules.
+ */
+export function computeCacheTTL(input: CacheTTLInput): number | null {
+  const {
+    closedFlag,
+    closedDate,
+    expectedCloseDate,
+    lastUpdated,
+    now = new Date(),
+  } = input;
+
+  const nowMs = now.getTime();
+
+  /**
+   * Check whether a date falls within a window around `now`.
+   *
+   * "Within" means the date is between `now - windowMs` and `now + windowMs`,
+   * allowing both past updates and future-scheduled dates to qualify.
+   */
+  const isWithinWindow = (date: Date | null, windowMs: number): boolean => {
+    if (!date) return false;
+    const diff = Math.abs(nowMs - date.getTime());
+    return diff <= windowMs;
+  };
+
+  // Rule 1 — Closed records
+  if (closedFlag) {
+    // Rule 1b — Recently closed (within 30 days) → cache at low-activity TTL
+    if (isWithinWindow(closedDate, THIRTY_DAYS_MS)) {
+      return TTL_LOW_ACTIVITY;
+    }
+    // Rule 1a — Closed longer than 30 days → do not cache
+    return null;
+  }
+
+  // Rule 2 — High activity (5 days)
+  if (
+    isWithinWindow(expectedCloseDate, FIVE_DAYS_MS) ||
+    isWithinWindow(lastUpdated, FIVE_DAYS_MS)
+  ) {
+    return TTL_HIGH_ACTIVITY;
+  }
+
+  // Rule 3 — Moderate activity (14 days)
+  if (
+    isWithinWindow(expectedCloseDate, FOURTEEN_DAYS_MS) ||
+    isWithinWindow(lastUpdated, FOURTEEN_DAYS_MS)
+  ) {
+    return TTL_MODERATE_ACTIVITY;
+  }
+
+  // Rule 4 — Low activity / stale
+  return TTL_LOW_ACTIVITY;
+}